Process of conditioning sand for foundry use



June 8 1926.

G. WALTHER PROCESS orconnmoume SAND'FOR FOUNDRY USE 1924 2 Sheets-Sheet1 Filed April 4 //v VE/V 7-0/3 7 M,

June 8 1926.

G. WALTHER PROCESS OF CONDITIONING S-AND FOR FOUNDRY USE Filed April 4,1924 2 Sheets-Sheet 2 WVE Tb/z WW1;

,4 770/?NEY Patented June 8, 1926.

UNITED STATES 1,587,621 PATENT OFFICE.

GEORGE WALTHER, OF MONTGOMERY COUNTY, NEAR DAYTON, 0310, ASBIGNOR TO THEDAYTON STEEL FOUNDRY COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

PROCESS OF CONDITIONING SAND FOR FOUNDRY USE.

Application filed April 4, 1924. Serial No. 704,208.

This invention relates to a new and useful process of, and means for,conditioning sand for foundry use, and relates particularly to aprogressive method of conditioning new and old sand for molding.

Used or hea sand, after being removed from the m0 ds, is first cleanedof all foreign substances such as wires, nails and metal particles whichmay get into it from the spilling of the molten metal, and also of allunusable or refuse sand.

Since at this point the used sand is still too hot from the castings tobe used immediately, it is one of the principal objects of my inventionto' cool the used sand to a normal temperature by suitable agitating andair blast means.

A concurrent step in my sand conditioning process is the drying of thenew sand which, when received at the foundry, usually has a moisturecontent that is too high for use. By suitable agitating and heatprojecting means, the new sand is dried at the same time the old sand iscooled.

The heap sand which has been cooled and the new sand that has beendried, are then properly proportioned and discharged automatically upona conveyor by which they are carried to a bar mill where they are mixedand milled, or, in the nomenclature of the foundry, conditioned. Thismay be accomplished by any suitable means such as a revolving cylinderin which loose bars or balls increase the mixing action of the sand sothat it may be discharged properly conditioned and ready for use in themolds. 1

Under my process the used sand need notv be cooled, nor the new sanddried, separately, but the cooling of the old sand and the dryingof thenew sand may be accomplished by mixing them together in a suitablecontainer such as a revolving cylinder, where the heat of the used sandevaporates the dampness of the new vsand; The used and the new sandwhile thus being mixed, are subjected to an air blast to aid intempering the admixture by neutralizinlg the ex-. cess of heat in theold sand and the excess of dampness in the new.

The used sand and the new sand thus tempered, are then carried to thebar mill where a thorough mixture of the new and old sand is elfected bysuitable agitating" devices such as round bars or balls,

preparatory for delivery to the. mac mes.

My process may be further simplified by passing the new sand direct fromthe sand storage, and the old sand direct from the cleaning means, tothe bar mill where, the new and old sand are thoroughly mixed togetherin the presence of a. blast of air which neutralizes the excess ofmoisture in the former and the excess of heat in the latter.

From the bar mill, where its mixture is effected by suitable agitatingdevices, the new sand and the used sand are discharged as a properlyconditioned mixture for delivery by suitable means to the conditionedsand pits and from them to the molding machines.

In its natural state the sand is ver open and without bmder. To give itconsistency anartificial binder such as fire cla is applied to it,accompanied by a t orough mixing, so that the crystals of the sand maybe coated with the binder to produce the proper adhesiveness during myprogressive conditioning process.

Methods heretofore used are subject to the whims of the o erator, whocan discharge the sand be ore it is thoroughly mixed. In my process thesand is handled automatically and cannot be discharged from the milluntil it is thoroughly mixed. The time of mixing is predetermined by theincline of the mill, the quantity and weight of the agitating bars orballs and the speed at which the mill is revolved.

in the accompanying drawings, Figure l is a panoramic view of the meansfor carrying into eifect my process when separate devices are providedfor cooling the old sand and drying the new sand. Figure 2 is a sideelevationali view of the temperin and mixing means that may be employefor accomplishing my. process when the molding new sand and the old'sandare mixed to-.

gether, and subjected to a blast of air, in a revolving cylinder, priorto their introduction in a tempered condition to the bar mill. And-Figure 3 is. a side elevational view of the means. I employ for carryinginto effect my process when the admixture of the new and old sand iscarried on in the bar mill itself. I I

The hot used sand and the moist new sand may be properly conditioned formolding by my progressive process before outlined, by the use of searate means for coohng the used sand an dryin'g the new sand, or byperforming that operation in a single cylinder in the presence of an airblast, fore the tempered mixture enters the bar mill, or thoseoperations may be accomplished in the bar mill itself, or any place alothe line.

. en the cooling and drying operations are performed separately, Ipreferably emloy the progressive means illustrated 1n i re 1. Includedwithin these means is a suitablea 'tating device 1' from which the heapsan from the shake-out is received, thoroughly agitated and depositedupon a suitable conveyorsuch as the belt 2 which asses over a magneticpulley 3 in a screenmg device 4. From the latter the refuse isdischarged by a chute 5 u on a ile while the screened sand passest rougthe device and is deposited upon a'conveyer belt 7. By this belt thescreened used sand is carried to the base of a suitable elevator 8 whichraises it and discharges it into a suitable cooling cylinder 9, where itis agitated by a suitable agitating device 10 therein. Into thiscylinder a blast of air is blown through a tube 11 to cool the used sandto a normal temperature during its agitation. s I

The screened used sand thus cooled is automatically de osited upon aconveyer such as the belt 12, y which it is carried to a bar mill 13preferably on a floor 14 below. The latter is preferably the firstfloor, upon which the screenin device 4 and the agitating device 1. area so supported. The cooling cylinder 9 is preferably mounted on thesecond floor 15. (See Figure 1.)

Also mounted on the second floor 15, opposite the cooling cylinder 9,is-a suitable drying cylinder 16 which receives the new sand through ,achute 17. This new sand, which ordinarily has a high moisture content,is dried in this cylinder by any suitable means such as the oil flame 18projected into the cylinder from a burner 19 secured in its inner head.Secured within the cylinder 16 v are axial agitating members 20 so thatwhen the cylinder is revolved by suitable driving means, the new sandwill be thoroughly agitated in it while .exposedto the flame 19.

. The c linder 16 automatically discharges the dri new sand upon aconveyer belt 12 in the sand w i is automatically de osited;u on thebelt in proper proportions y the cylinder 9. The new and the" old sandare then conveyed together to the bar mill 13 where they are thoroughlymixed and milled by round bars or other suitable elements therein whichincrease the mixing action when the "mill isrotated. v

' 'lhe sand thus conditionedis deposited in the bottom part ofanelevator 22 by which means.

roger proportions to the cooled old it is raised for discharge intomolding machine pits 23. By means of an elevator 24 the conditioned sandmay then be raised from these pits and delivered to a chute 25 whichdischarges it into the molding machines 26.

As before brought out, the used sand may be cooled and the new sanddried by mixture together in a cylinder where the heat of the used sandwill eva crate the dampness of the new sand. Thls combined step of myprocess may be carried out in any suitable device such as the cylinder27 shown in Figure 2. The used sand which has been cleaned and screenedby any suitable means such as those shown in Figure 1, is delivered,with the new sand from the new sand storage, into a chute 28 on thecylinder 27, the latter adapted to be revolved by any suitable To thischute the old sand is delivered by the elevator 8, and the new sand bya'conveyer belt 29.

Secured within the cylinder 27 are suitable agitating members 30 forthoroughly mixing the used and the new sand to permit the heat of theformer to evaporate the dampness of the latter. Projecting into thechute end of the c linder 27 is a tube 31 in an air line from a an orblower (not shown) through which a blast of air is projected into thecylinder to aid in tempering the mixed sand by neutralizing the excessof heat in the used sand and the excess of dampness in the old sand.

The admixture of the used sand and the new sand thus tempered, isdischarged from the rear end of the cylinder 27 upon a'conveyer belt 32by which it is carried to a bar mill 33, where it is thoroughly mixedand milled in the same manner as in the bar mill 13. The conditionedsand is then discharged by the bar mill 33 into the lower portion of anelevator 34 by which it is delivered to the conditioned sand pits 23shown in Fi and from thence to the molding machines 26 by the meanstherein outlined.

I As a more simplified form of my process, the used sand from thecleaning means, and the new sand from the new sand stora e, may bedelivered directly to the bar mill or the purpose of conditioning withrespect to coolm the used sand, dr ing the new sand and t oroughlymixing t em together. In Fi re 3 I have illustrated a bar mill 35 provied with an end chute 36 in which the used sand is depositedby theelevator 8 and to which the new sand is conveyed by the belt 29. Withinthis bar mill which 1s revolved by suitable means, are round bars 37that preferably run the length of the bar mill to increasethemixingaction, although other suitable agitating devices could be emplo ed ifdesired.

- y means of an air line 38 from a fan or blower not shown, an air blastmay be pro- III jected into the bar mill 35 during the mixing operation,to temper the admixture by neutralizin the excess of heat in the oldsand and t e excess of moisture in the new sand. If the new sand shouldcome to the bar mill dry, as in warm weather, and the used sand shouldbe delivered to it after standing a sufiicient time to cool, then theair blast may be reduced or shut-ofi entirely. The new sand and the usedsand when tempered and mixed in the bar mill '35, may be delivered tothe molding machines by the means illustrated and described.

In order to impart consistency to the sand so that it may hold itsshape, a bindersuch as fire clay should be added, and thoroughly.

mixed with it, to coat the crystals of the sand to produce the pro eradhesiveness.

Under my process t e sand is handled automatically and can not bedischarged from the bar mill until it is thoroughly mixed. Furthermore,the process is progressive, economical and efiicient, and eliminatesmany separate and distinct steps and operations which areby my methodcombined in a progressive and unified whole.

It is also possible under my process to just condition the oldsand inthe bar mill, and use it as facing and molding sand and occasionally mixit with the new sand.

Having described my invention, I claim: 1. The herein describedprocess-of mixmg new sand and old sand for molding, which consists inbringing the new sand and the old sand together, and then introducingair into the mixture to neutralize the excess of dampness in the newsand and the excess of heat in the old sand.

' 2. The herein described process of conditioning new sand and old sandfor molding, which consists in bringing the new sand and the old sandtogether, then introducing air to themixture to neutralize the excess ofdampness in the new sand and the excess of heat in the old sand, andthen mixing the tempered new sand and old sand.

3. The herein described process of 0011- ditioning new sand and old sandfor molding, which consists in first bringing the.

new sand and the old sand together, then introducing the same to amixing. chamber,

5. The herein described process of conditioning sand for molding, whichconsists in mixing new sand and old sand together while subjected to ablast of air, and thereafter mixing and milling the tempered sand.

6. The herein described process of conditioning sand for molding, whichconsists in revolving new sand and old sand together while subjected toa blast of air, and thereafter revolving the tempered sand.

' 7. The herein described process of conditioning' sand for molding,which consistsin first cleaning old sand, then mixing it' with new sandwhile subjected to a blast of air, and thereafter mixing and milling thetempered sand.

In witness whereof I have hereunto set my hand this 2nd day of April,1924.

GEORGE WALTHER,

